title: Noninvasive fractional flow reserve derived from computed tomography angiography for coronary lesions of intermediate stenosis severity: results from the DeFACTO study.
abstract: BACKGROUND
  Fractional flow reserve derived from computed tomography angiography (FFRCT) is a noninvasive method for diagnosis of ischemic coronary lesions. To date, the diagnostic performance of FFRCT for lesions of intermediate stenosis severity remains unexamined.
  
  
  RESULTS
  Among 407 vessels from 252 patients at 17 centers who underwent CT, FFRCT, invasive coronary angiography, and invasive FFR, we identified 150 vessels of intermediate stenosis by CT, defined as 30% to 69% stenosis. FFRCT, FFR, and CT were interpreted in blinded fashion by independent core laboratories. FFRCT and FFR ≤0.80 were considered hemodynamically significant, whereas CT stenosis ≥50% was considered obstructive. Diagnostic performance of FFRCT versus CT was assessed for accuracy, sensitivity, specificity, positive predictive values, and negative predictive values. Area under the receiver operating characteristic curve and net reclassification improvement were evaluated. For lesions of intermediate stenosis severity, accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of FFRCT were 71%, 74%, 67%, 41%, and 90%, whereas accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of CT stenosis were 63%, 34%, 72%, 27%, and 78%. FFRCT demonstrated superior discrimination compared with CT stenosis on per-patient (area under the receiver operating characteristic curve, 0.81 versus 0.50; P=0.0001) and per-vessel basis (area under the receiver operating characteristic curve, 0.79 versus 0.53; P<0.0001). FFRCT demonstrated significant reclassification of CT stenosis for lesion-specific ischemia (net reclassification improvement, 0.45; 95% confidence interval, 0.25-0.65; P=0.01).
  
  
  CONCLUSIONS
  FFRCT possesses high diagnostic performance for diagnosis of ischemic for lesions of intermediate stenosis severity. Notably, the high sensitivity and negative predictive value suggest the ability of FFRCT to effectively rule out intermediate lesions that cause ischemia.
authors.affiliation: St. Luke's International Hospital, Tokyo, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Nakazato
authors.forename: Hyung-Bok
authors.initials: HB
authors.lastname: Park
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Berman
authors.forename: Heidi
authors.initials: H
authors.lastname: Gransar
authors.forename: Bon-Kwon
authors.initials: BK
authors.lastname: Koo
authors.forename: Andrejs
authors.initials: A
authors.lastname: Erglis
authors.forename: Fay Y
authors.initials: FY
authors.lastname: Lin
authors.forename: Allison M
authors.initials: AM
authors.lastname: Dunning
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Budoff
authors.forename: Jennifer
authors.initials: J
authors.lastname: Malpeso
authors.forename: Jonathon
authors.initials: J
authors.lastname: Leipsic
authors.forename: James K
authors.initials: JK
authors.lastname: Min
mesh_terms: D017023:Coronary Angiography / Q000379:methods*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D053805:Fractional Flow Reserve, Myocardial / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed
keywords: fractional flow reserve, myocardial